The BLACK HOLE Subwoofer (1 Viewer)

[ChrisA]

Room for the drivers - not a problem for me but not everyone could make it work. I'm running stereo line arrays of 6 Peerless 12" each, 12 drivers total. The backwave goes into the garage. I could easily add more lines beside the ones I have but my picture window can't handle full volume now so I don't see the need. The biggest hassle with big IBs is moving them to a new location. I'm planning that now. The actual speakers are easy to move - just an 18" wide baffle with 6 drivers in a line. Two people can easily carry it. I'm still working on the logistics of installing them in the new house so they have adequate volume behind them.

Sounds outstanding! What crossover type/point/slope do you use? I am still debating on 'stereo' IB vs 'mono' IB. I have not yet decided, however, I have 1-3 years to think about it... It will depend in the size of the room, etc... In either case I don't plan on using higher than a 50 Hz crossover. Stereo I would consider using as high as 60 Hz fourth order, however, if Mono, I would probably want to keep it closer to 40 Hz. I have lots of time to think about it. I will always stick with full-range types of speakers all the way around to allow for lower crossover settings. Ultimately 'one corner' vs two 'corners' will depend on the size of the room, the main speakers, SPL goals, etc... which have yet to be determined.
You could fit (4) 18 inch 'Ultimate' IB drivers (yet to be named) per side, for 8 drivers total The 'ultimate' IB drivers should provide some significant advantages over the peerless...

 

[Dennis XYZ]

You could fit (4) 18 inch 'Ultimate' IB drivers (yet to be named) per side, for 8 drivers total The 'ultimate' IB drivers should provide some significant advantages over the peerless...

Yeah, nothing special about those Peerless drivers (similar to the current Classic 12".) I built this thing years ago, before I was on the internet, and just used what my buddy who owns a hi-fi store recommended. I think I paid about $60 each. I'm sure your Uber 18s would move some serious air but it might get expensive repairing the room after every movie. Even my crummy little short-stroke 12s can do structural damage.

 

[ChrisA]

I'm sure your Uber 18s would move some serious air but it might get expensive repairing the room after every movie. Even my crummy little short-stroke 12s can do structural damage.

I think the key here is performance, not just SPL.

You would probably need a total of 4 such drivers (instead of 12 total you now have) for similar/greater SPL outputs. Headroom is also nice as you already know.

In your case, 4 drivers is easier to manage impedance-wise, with less amplifiers. Which would be true for anybody for that matter.

Most importantly, you would have drivers that perform perfectly for your IB application. No doubt such a driver would produce significant audible benefits. We need a 'balls to the wall' IB driver that was designed exclusively for IB. Everybody just wants to mass load a stiff suspension... forget it! We need to design a very compliant, huge VAS, low Fs, IB driver that ends up with a Qts of 0.45-0.5. I will certainly be setting aside money for this driver project...

 

[Dennis XYZ]

Everybody has their own price/performance area they want to target.

Let's just say we have different design goals and define "performance" differently. I guess that's why they sell more than one brand of speakers. By my definition of performance, (5*X) Tempests at $120(?) each will almost certainly outperform (1*X) drivers at $600 each. The difference will be measureable in terms of max SPL, linear distortion and especially nonlinear distortion. Quantity directly translates into sound quality when you start playing with arrays. Efficiency also skyrockets with big arrays. One of my fantasies was to cover the whole ceiling with Tempests or Shivas about 4' on center but I never got "permission" for that one.

 

[JoeyT]

My god man... Too much bilirubin, too much cholesteral, and not enough bile salts/acids in the exogenous pathway and you are on a mission to dissolve gallstones from home. Btw, how much is your copay I know you are an intern but be kind to your neighborhood and at least sound the siren before you fire up those subs...please:frowning:

 

[ChrisA]

By my definition of performance, (5*X) Tempests at $120(?) each will almost certainly outperform (1*X) drivers at $600 each. The difference will be measureable in terms of max SPL, linear distortion and especially nonlinear distortion. Quantity directly translates into sound quality when you start playing with arrays.

That is if the only aspect you are measuring is percentage of linear excursion travelled as well as max SPL capability. But again, I don't think you are weighing in the benefit of a driver which NATURALLY performs well to acheive a specific response, vs a driver that requires significant electronics to achieve a desired response.
Further, you are not talking about performance. If you were talking about performance, why on earth would you compare 5 tempests to 1 super driver? You wouldn't. You would simply buy 5 super drivers and compare that to 5 Tempests.
I don't care if you had a hundred tempests, it wouldn't change the character of the driver. You are acting as if the character and T/S parameters of the driver can be perfectly adjusted electronically, and also as if there were no penalty for doing so.
Let's determine real performance: I'll take the best driver for the application and use as many as I need to reach the SPL requirements I need... fairly simple. Why set up arguments that confuse the issue?
P.S. I was an intern two years ago You must be talking about kidney stones... If you have problems with gallstones, they just yank it out. I'll give you some Shock wave therapy...

 

[Jack Gilvey]

Chris, you seem to know exactly what you want, why not just make it happen? If you really want this driver, and have the space to use it, then have a run of them made.

I wouldn't wait for someone to produce it, even though it may fit your specific performance goals, there's just too limited a market for it I think. Such a driver would probably be exceptional in a dipole also.

 

[ChrisA]

The problem is that it would require at least a run from anywhere from 50-500. Obviously the more that are made, the les the cost per driver, however, I'd need to have 'some' interest in the driver by other people to make it happen. In any case, this is a 'near future' project for me personally, but I jusmped in because of all of the talk about the Tumult as well as the prospect of an 18 inch version of the Tumult geared more for IB...

 

[Jack Gilvey]

Here are some specs DanW posted early on in the "perfect sub driver"/Tumult thread for a potential 18" IB/dipole driver:

Sd: 1140 cm^2

Xmax: 35mm one way

Fs: 14.5 Hz

Qms: 24

Qes: 0.45

Vas: 360L

Re: 5.4 Ohms (two in parallel for a nominal 4 Ohm load)

Le: 4.3 mH

Motor-based distortion under 5% @ 30mm one way

This was pulled off the table early on in favor of the more "general-purpose" 15", and it hasn't quite the Vas you were looking for I think (the XBL2 technology probably has the capability to allow for softer suspensions/high Vas/high excursion linearity, however). Neat, though. Point is, Dan might be someone to talk to about it.

 

[ChrisA]

The key is as you said, being able to use a more compliant suspension...

Hopefully Dan will be able to do an 18 inch driver similar to what is listed by you directly above, but with a larger Vas (as large as possible), *slightly* lower Fs (13-14 Hz), and with a Qts so that the natural variation of the production models fall within the 0.45-0.5 range.

 

[Steve Hanna]

It's nice to see this thread again. Aura/Seismic 18" pro drivers rock the house. As drivers advance, us DIYers get used to the level of performance and then demand some more performance. It's the kind of viscious cycle I like to see.

 

[Steve Hanna]

It's nice to see this thread again. Aura/Seismic 18" pro drivers rock the house. As drivers advance, us DIYers get used to the level of performance and then demand some more performance. It's the kind of viscious cycle I like to see.

 

[Bill Fagal]

Chris,

Your talk of financing a new superdriver perked my ears up, since I'm sitting on a design I believe fills the bill--a complete rethink of the LF transducer. I'm just saving up to prototype it and get some real-world measurements/R&D done. Since I have a day job and bills to pay, things aren't moving forward with the gusto I would like.

Some bullet points:

60mm of one-way Xmag

70mm of one-way Xsus

Sd = 1090 cm^2

About 14L displacement per cycle

If that's only somewhat interesting to you, I'll also mention that the suspension/surround exhibits virtually no return force most of the way to Xsus (sounds impossible, I know). In fact, return force will be dictated by an entirely seperate means, allowing you to cherrypick it as an independant variable for a variety of applications.

If I find that prototyping this idea is beyond my means, I may be interested in raising external funding and perhaps forging a partnership or two to bring it to market.

Bill

 

[Hank Frankenberg]

Bill, do you have a conservative estimate of the market potential via good research? What sort of development costs are you estimating?

 

[Bill Fagal]

No research, but when it comes to market potential, it's healthy to assume the worst. However, if the prototype approaches my performance projections, the worst should be none too bad!
Development costs depend on how much prototyping/R&D lies between now and rollout. To an even greater extent, they depend on what processes I settle on for production. For example, the unique diaphragm must be either hand-fabbed or molded--big difference in development costs there. After I complete the machinist drawings and tweak the prototype, I'll be gathering more accurate cost estimates.
BTW, I don't mean to be threadjacking here, I just thought I'd mention that something cool is in the works.
Bill

 

[Hank Frankenberg]

Bill, okay, let's take this offline. You might want to start a thread re your development project to guage interest and then correspond via e-mail with serious inquirers or potential investors. If you want, send me an e-mail with the details you'd disclose. I might be willing to sign a CDA (Confidential Discolsure Agreement - that's what we call 'em at work - I do them all the time with suppliers). I know about plastic injection molding and the high prices of tooling - that's for high volume.

 

[Brian Bunge]

I might be willing to sign a CDA

Same here!

 

[Bill Fagal]

I'd like to start a thread, but it would have to remain a little threadbare since my previous post revealed about all I feel comfortable revealing right now, short of a signed NDA.

Obviously, the keystone of my design is the suspension and surround, so I really can't even release illustrations publicly until a patent is in. Since I have yet to define the specific areas of product develoment that I cannot conquer alone, all I can do is serve notice that this driver is in the works and possibly invite interested parties to suggest ways they could contribute. When needs arise, I'll come knocking. What I really need right now is some good advice from insiders about development processes and how to proceed from a business standpoint. Sadly, I am much more engineer than businessman.

When I can reveal more, or when I need specific help, I'll start a thread, as you suggest. Trouble is, I'm too excited about this project to keep quiet, so it spills out of me from time to time.

If you have some good ideas of how to help me out, I'd consider disclosing more under the protection of an NDA.

'preciate your interest,

Bill

 

[Hank Frankenberg]

Bill, I don't want to mess with Chris' thread, so YGM.

 

[Jack Gilvey]

Don't know how long these processes take, but it looks like we'll have a new driver to drool over around the time Tumult Mk.3 is released.